<div mat-subheader class="header-container">
    <div>
        <h3>{{header}}</h3>
    </div>
    <div class="fill">
        <button mat-button (click)="onNewTaskClick()">
      <mat-icon class="mat-18">add_circle_outline</mat-icon>
      <span>新任务</span>
    </button>
    </div>
    <div>
        <button mat-button [matMenuTriggerFor]="menu">
      <mat-icon>keyboard_arrow_down</mat-icon>
    </button>
    </div>
</div>
<mat-menu #menu="matMenu">
    <button mat-menu-item (click)="editListClick()">
    <mat-icon>mode_edit</mat-icon>
    <span>修改列表名称</span>
  </button>
    <button mat-menu-item (click)="onMoveAllClick()">
    <mat-icon>mode_edit</mat-icon>
    <span>移动本列表所有内容</span>
  </button>
    <button mat-menu-item (click)="onDelete()">
    <mat-icon>delete_forever</mat-icon>
    <span>删除列表</span>
  </button>
</mat-menu>